Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH 0/5] iommu/vt-d: debugfs: Enhancements to IOMMU debugfs | Date | Tue, 4 Jul 2023 07:54:58 +0000 |
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> From: Liu, Jingqi <jingqi.liu@intel.com> > Sent: Monday, July 3, 2023 10:37 PM > > On 7/3/2023 3:15 PM, Tian, Kevin wrote: > >> From: Liu, Jingqi <jingqi.liu@intel.com> > >> Sent: Sunday, June 25, 2023 11:05 PM > >> > >> The original debugfs only dumps all IOMMU page tables without pasid > >> supported. It traverses all devices on the pci bus, then dumps all page > >> tables based on device domains. This traversal is from software > >> perspective. > >> > >> This series dumps page tables by traversing root tables, context tables, > >> pasid directories and pasid tables from hardware perspective. By > >> specifying source identifier and PASID, it supports dumping specified > >> page table or all page tables in legacy mode or scalable mode. > >> > >> For a device that only supports legacy mode, specify the source > >> identifier, and search the root table and context table to dump its > >> page table. It does not support to specify PASID. > >> > >> For a device that supports scalable mode, specify a > >> {source identifier, PASID} pair and search the root table, context table > >> and pasid table to dump its page table. If the pasid is not specified, > >> it is set to RID_PASID. > >> > >> Switch to dump all page tables by specifying "auto". > >> > >> Examples are as follows: > >> 1) Dump the page table of device "00:1f.0" that only supports legacy > >> mode. > >> > >> $ sudo echo 00:1f.0 > > >> /sys/kernel/debug/iommu/intel/domain_translation_struct > >> $ sudo cat /sys/kernel/debug/iommu/intel/domain_translation_struct > >> Device 0000:00:1f.0 @0x105407000 > >> IOVA_PFN PML5E PML4E > >> 0x0000000000000 | 0x0000000000000000 0x0000000105408003 > >> 0x0000000000001 | 0x0000000000000000 0x0000000105408003 > >> 0x0000000000002 | 0x0000000000000000 0x0000000105408003 > >> 0x0000000000003 | 0x0000000000000000 0x0000000105408003 > >> > >> PDPE PDE PTE > >> 0x0000000105409003 0x000000010540a003 0x0000000000000003 > >> 0x0000000105409003 0x000000010540a003 0x0000000000001003 > >> 0x0000000105409003 0x000000010540a003 0x0000000000002003 > >> 0x0000000105409003 0x000000010540a003 0x0000000000003003 > >> > >> [...] > >> > >> 2) Dump the page table of device "00:0a.0" with pasid "2". > >> > >> $ sudo echo 00:0a.0,2 > > >> /sys/kernel/debug/iommu/intel/domain_translation_struct > >> $ sudo cat /sys/kernel/debug/iommu/intel/domain_translation_struct > > What about creating a directory layout per {dev, pasid} so the user can > > easily figure out and dump? > > > > e.g. > > > > /sys/kernel/debug/iommu/intel/00:0a.0/0/domain_translation_struct > > /sys/kernel/debug/iommu/intel/00:0a.0/2/domain_translation_struct > Thanks. > > Do you mean create a directory for each device, whether it supports > PASID or not ?
every device has PASID#0 valid, i.e. RID2PASID.
> Seems the PASID can be assigned at runtime. > So it needs to support creating debugfs file at runtime in IOMMU driver. > Looks like this requires modifying IOMMU driver. >
Isn't this patch trying to modify the driver?
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